James Cameron's battle for Avatar investment

James Cameron had to film 40 seconds of 'Avatar' - the highest grossing movie at the box office of all time - in order to convince a studio to invest in it.

James Cameron had to film 40 seconds of 'Avatar' to convince a studio to invest in it.

The director's 3-D movie adventure pushed the boundaries of filmmaking and set a new precedent for how realistic movies could be - as well as setting a box office record by grossing $2.8 billion - but Cameron found it wasn't easy to get the funding to make it.

He told France's TF1 TV channel: ''It's always difficult to convince any Hollywood studio to make a technically-challenging film.

''We convinced them by filming 40 seconds of what the film was going to look like. As soon as they saw the 3d test, they understood what we wanted to do.

''I think 'Avatar' represented the latest thing in terms of new images. In this case, the classic story which cinemagoers can identify with works a bit like a gateway into the visual universe 'Avatar' offers.''

Although his movie opened the floodgates to a new era in cinema, Cameron doesn't think the basic structure behind all good movies will ever change.

He added: ''Technology will definitely evolve, the context will chance, but it won't ever change the fact that to make a good move, you have to have a good story and interesting characters. That's why people still want to leave their houses and sit in a darkened room with others to experience it. I don't think it'll ever stop.''